Haptic output device and method of generating a haptic effect in a haptic output device

ABSTRACT

A haptic output device includes a touch surface, a sensor configured to sense an input at the touch surface, and a controller configured to read the sensor, identify a location of the input, switch from a read mode to a write mode, and write a voltage based on the location of the input to generate an electrostatic output.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/078,335, filed Mar. 23, 2016, which is a continuation of U.S. patentapplication Ser. No. 13/605,589, filed Sep. 6, 2012, which claims thebenefit of priority from U. S. Provisional Patent Application No.61/531,251, filed Sep. 6, 2011, the entire content of all areincorporated herein by reference.

FIELD

The present invention is related to a haptic output device and a methodof generating a haptic effect in a haptic output device.

BACKGROUND

Touch sensitive surfaces, also known as touch surfaces, are used in avariety of applications. For example, a touch surface may be provided bya touch screen, for example a capacitive touch screen, a touch pad, forexample in a laptop, or an automotive controller. Touch surfaces do nottypically provide haptic effects to the users of the touch surfaces. Itis desirable to provide a haptic output device that provides hapticeffects when a user interacts with the touch surface of the hapticoutput device.

SUMMARY

According to an aspect of the present invention, there is provided ahaptic output device that includes a touch surface; a sensor configuredto sense an input at the touch surface; and a controller configured toread the sensor, identify a location of the input, switch from a readmode to a write mode, and write a voltage based on the location of theinput to generate an electrostatic output.

In an embodiment of the haptic output device, the haptic output deviceincludes a touch screen comprising the touch surface.

In an embodiment of the haptic output device, the touch screen is acapacitive touch screen.

In an embodiment of the haptic output device, the controller isconfigured to write the voltage to an entire area of the capacitivetouch screen.

In an embodiment of the haptic output device, the controller isconfigured to write the voltage to an area proximate the location of theinput.

In an embodiment of the haptic output device, the sensor is configuredto sense a plurality of inputs, and wherein the controller is configuredto identify locations of the inputs on the touch surface.

In an embodiment of the haptic output device, the controller isconfigured to write the voltage to areas corresponding to the locationsof the inputs to generate a plurality of localized electrostaticoutputs.

In an embodiment of the haptic output device, the capacitive touchscreen comprises an insulating outer layer comprising the surface, andan electrode proximate the insulating outer layer, wherein the electrodeis configured to generate the electrostatic output.

In an embodiment of the haptic output device, the haptic output deviceincludes a plurality of electrodes proximate the insulating outer layer,wherein the controller is configured to drive at least one electrode ofthe plurality of electrodes closest to the location of the input togenerate the electrostatic output.

In an embodiment of the haptic output device, the haptic output deviceincludes a plurality of electrodes proximate the insulating outer layer,wherein the controller is configured to drive different electrodes ofthe plurality of electrodes to generate multi-touch localizedelectrostatic outputs.

In an embodiment of the haptic output device, the haptic output deviceincludes a plurality of electrodes proximate the insulating outer layer,wherein the controller is configured to write the voltage to one of theplurality of electrodes proximate a first location, then write thevoltage to another one of the plurality of electrodes proximate a secondlocation to transition the electrostatic output from the first locationto the second location as the input is moved from the first location tothe second location.

In an embodiment of the haptic output device, the controller isconfigured to modulate an overall power delivered by each electrode ofthe plurality of electrodes according to a current location of theinput.

In an embodiment of the haptic output device, the overall powerdelivered by each electrode is a function of the location of the inputrelative to each electrode.

According to an aspect of the present invention, there is provided amethod for generating a haptic effect at a surface of a haptic outputdevice comprising a touch surface. The method includes sensing an inputon the touch surface with a sensor; reading a first voltage from thesensor sensing the input on the touch surface with a controller;determining a location of the input with the controller; switching thecontroller from a read mode to a write mode; and writing a secondvoltage based on the sensed location of the input, with the controller,to generate an electrostatic output.

In an embodiment of the method, the touch surface is provided by acapacitive touch screen.

In an embodiment of the method, the writing comprises writing the secondvoltage to an entire area of the capacitive touch screen.

In an embodiment of the method, the writing comprises writing the secondvoltage to an area proximate the sensed location.

In an embodiment of the method, the sensing comprises sensing aplurality of inputs and locations of the inputs on the touch surface.

In an embodiment of the method, the writing comprises writing the secondvoltage to areas corresponding to the locations of the inputs togenerate a plurality of localized electrostatic outputs.

In an embodiment of the method, the capacitive touch screen comprises aninsulating outer layer comprising the touch surface, and an electrodeproximate the insulating outer layer. The electrode is configured togenerate the electrostatic output.

In an embodiment of the method, the capacitive touch screen comprises aplurality of electrodes proximate the insulating outer layer, and themethod includes driving at least one electrode of the plurality ofelectrodes, with the controller, closest to a location to generate theelectrostatic output.

In an embodiment of the method, the capacitive touch screen comprises aplurality of electrodes proximate the insulating outer layer, and themethod comprises driving different electrodes of the plurality ofelectrodes, with the controller, to generate multi-touch localizedelectrostatic outputs.

In an embodiment of the method, the capacitive touch screen comprises aplurality of electrodes proximate the insulating outer layer, and themethod includes writing the second voltage to one of the plurality ofelectrodes proximate a first location, with the controller, sensing asecond input at a second location with a sensor, determining the secondlocation with the controller, and writing the second voltage to anotherone of the plurality of electrodes proximate the second location totransition the electrostatic output from the first location to thesecond location as the input is moved from the first location to thesecond location.

In an embodiment of the method, the method includes modulating, with thecontroller, an overall power delivered by each electrode according to acurrent location of the input.

In an embodiment of the method, the overall power delivered by eachelectrode is a function of the location of the input relative to eachelectrode.

In an embodiment of the method, the method includes measuring impedanceat the touch surface at the location of the input, and adjusting thewriting the second voltage to adjust the electrostatic output.

In an embodiment of the method, the impedance is measured by the sensor.

According to an aspect of the present invention, there is provided amethod for generating a haptic effect at a surface of a haptic outputdevice comprising a touch surface. The method includes sensing an inputon the touch surface with a sensor; reading a first voltage from thesensor sensing the input on the touch surface with a controller;determining a location of the input with a controller; and writing asecond voltage based on the sensed location of the input to generate anelectrostatic output with the controller.

In an embodiment of the method, the second voltage is about the same asthe first voltage.

In an embodiment of the method, the second voltage comprises a dynamicvoltage value.

In an embodiment of the method, the touch surface is provided by acapacitive touch screen comprising a plurality of electrodes, and thewriting the second voltage comprises writing the second voltage to atleast one electrode proximate the location of the input.

In an embodiment of the method, the method includes measuring impedanceat the touch surface at the location of the input, and adjusting thewriting the second voltage to adjust the electrostatic output.

In an embodiment of the method, the impedance is measured by the sensor.

The embodiments described in the present disclosure may include variousfeatures and advantages, which may not necessarily be expresslydisclosed herein but will be apparent to one of ordinary skill in theart upon examination of the following detailed description andaccompanying drawings. It is intended that these features and advantagesbe included within the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The components of the following figures are illustrated to emphasize thegeneral principles of the present disclosure and are not necessarilydrawn to scale. Reference characters designating correspondingcomponents are repeated as necessary throughout the figures for the sakeof consistency and clarity.

FIG. 1 schematically illustrates a haptic output device in accordancewith an embodiment of the present invention;

FIG. 2 schematically illustrates the haptic output device in accordancewith an embodiment of the present invention;

FIG. 3 schematically illustrates the haptic output device in accordancewith an embodiment of the present invention;

FIG. 4 schematically illustrates an embodiment of an insulating layer ofthe haptic output device of FIG. 2;

FIG. 5 is a flow diagram of a method for generating a haptic effect at asurface of a haptic output device; and

FIG. 6 is a flow diagram of a method for generating a haptic effect at asurface of a haptic output device.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of a user interface in the form of ahaptic output device 100 configured to provide a haptic effect to a userof the haptic output device 100. The haptic output device 100 may be,for example, part of tablet, a phone, a music player, a video player, agraphic display, an e-book reader, a gamepad, a touch pad, an automotivedashboard, a steering wheel, some combination of the aforementioneddevices, or may be some other general device that includes a userinterface. As illustrated in FIG. 1, the haptic output device 100includes a touch screen 110 having a touch surface 112, a display 120beneath the touch screen 110, and a controller 130, which are describedin further detail below. Although the embodiments described herein aredirected to a haptic output device 100 that includes a touch screen, itshould be understood that other embodiments within the scope of thepresent invention may not include a display and a touch screen, butinstead include the touch surface 112 without the touch screen. Theillustrated embodiment discussed herein should not be considered to belimiting in any way.

A haptic effect refers to a stimulus or force, including but not limitedto a vibration, an attractive or repulsive force, a voltage or current,some other mechanical or electromagnetic force, heating or cooling, orsome other stimulus. The haptic effect may comprise one force orstimulus or a combination of forces and/or stimuli. A plurality ofhaptic effects may be combined to form an overall haptic effect. Thehaptic effect may be output to provide feedback to a user or objectinteracting with the haptic output device 100. The haptic effect mayprovide feedback through an electrostatic output. In an embodiment, theelectrostatic output may be used to generate a force on an object, likea finger at the user interface, to simulate a friction force as thefinger is moved while in contact with the haptic output device 100 atthe user interface. In an embodiment, the electrostatic output may beused to send an electric signal, e.g., a voltage or current, to anobject that can perceive the signal, like a nerve of the finger or asensor in a stylus, which can provide a texture effect to the user.

In an embodiment, the touch screen 110 is a capacitive touch screen. Inan embodiment, the touch screen is a surface capacitive touch screen. Inan embodiment, the touch screen 110 is a projected capacitive touchscreen.

As illustrated in FIG. 1, the touch screen 110 may include a conductivelayer 114 and an insulating layer 116. The conductive layer 114 mayinclude any semiconductor or other conductive material, such as copper,aluminum, gold, silver, conductive polymers, carbon nanotubes, etc. Theconductive layer 114 may include a sensor 118 or a plurality of sensors.The insulating layer 116 may be glass, plastic, polymer, or any otherinsulating material.

The haptic output device 100 interfaces with the user by beingconfigured to sense an input, which may be an object that is touchingthe touch surface 112 of the touch screen 110, with the sensor 118. Theobject may be a user's finger F, as illustrated in FIG. 1, a palm of theuser's hand, or any other part of the user's body that can sense ahaptic effect. The object may also be a stylus or some other device thatcan be sensed to be touching the surface 112 of the touch screen 110.The haptic output device 100 may sense the presence of the objecttouching the surface 112 of the touch screen 110 through capacitive,resistive, or inductive coupling, but is not limited to thosetechniques.

The controller 130 may provide an electric signal to the conductivelayer 114. The electric signal may be an AC or time varying signal thatcapacitively couples the conductive layer 114 with an object near ortouching the touch screen 110. The AC signal may be generated by ahigh-voltage amplifier. The haptic output device 100 may also rely onprinciples other than or in addition to capacitive coupling to generatea haptic effect. The capacitive coupling may generate a haptic effect bystimulating parts of the object near or touching the touch screen 110,such as mechanoreceptors in the skin of a user's finger F or componentsin a stylus that can respond to the coupling. The mechanoreceptors inthe skin, for example, may be stimulated and sense the capacitivecoupling as a vibration or some more specific sensation, which maysimulate a texture or friction force, particularly when the finger F ismoved across the surface 112 of the touch screen. For example, theconductive layer 114 may be applied with an AC voltage signal from thecontroller 130 that couples with conductive parts of a user's finger F.

In an embodiment, the capacitive coupling may be provided to generate anelectrostatic output. In an embodiment, the capacitive coupling may beprovided to simulate a friction force or texture on the surface 112 ofthe touch screen 110. A friction force is simulated in that while thesurface 112 of the touch screen 110 may be smooth, the capacitivecoupling may produce an attractive force between an object near thetouch screen 110 and the conductive layer 114. The attractive forceincreases the friction on the surface 112 even when the topography ofthe material at the surface 112 has not changed. Varying the levels ofattraction between the object and the conductive layer 114 may vary thefriction on an object moving across the surface 112 of the touch screen110. Varying the friction force simulates a change in the coefficient offriction.

As the user touches the touch screen 110 and moves his or her finger Fon the touch screen 110, the user may sense a texture of prickliness,graininess, bumpiness, roughness, stickiness, an edge, a button, or someother texture via the electrostatic outputs that are generated. Texturedoes not have a coefficient of friction change on the surface 112, butinstead is created by specific sensations that are sensed by the user'sskin mechanoreceptors. The user's skin mechanoreceptors may also bestimulated to have a general sensation as the finger F moves across thetouch screen 110. Therefore, the capacitive coupling may be used tosimulate a friction force or texture by generating a signal that coupleswith an object near or touching the touch screen 110.

To provide the same attractive force or to provide the same level ofstimuli across many different objects or persons, the sensor 118 and/orcontroller 130 may measure the impedance at the surface 112 of the touchscreen 110. The sensor 118 and/or controller 130 may measure theimpedance by applying a pulse across the surface 112 and measuring thesurface voltage or by measuring the strength of the capacitive coupling.The sensor 118 and/or controller 130 may use other known techniques formeasuring impedance, and may compensate for varying ambient conditionssuch as the moisture in the air or temperature. The haptic effect may beadjusted based on the impedance of a person. For example, a moreforceful haptic effect may be applied to an object with higher impedanceand a less forceful effect for an object with lower impedance.

In an embodiment, the touch screen 110 may not have an insulating layer,so that an object can directly touch the conductive layer 114. A hapticeffect may be generated by passing an electrical current from theconductive layer 114 to the object.

As illustrated in FIG. 2, in an embodiment, the insulating layer 116 mayinclude one or more electrodes 122 in the insulating layer 116 that canpass current to objects that touch the surface 112 of the touch screen110 at a location proximate to the electrode(s) 122 as the objects moveacross the insulating layer 116.

As illustrated in FIG. 1, in an embodiment, the conductive layer 114 mayinclude one or more electrodes 124 that can generate an electrostaticoutput to objects that touch the surface 112 of the touch screen 110 ata location proximate to the electrode(s) 124 as the objects move acrossthe insulating layer 116. In an embodiment, an electrode that is part ofthe sensor 118 may generate an electrostatic output.

As illustrated in FIG. 3, in an embodiment, one or more electrodes 126,126A, 1266 may be located in between the conductive layer 114 and theinsulating layer 116. The one or more electrodes 126, 126A, 126B maygenerate an electrostatic output to the objects that touch the surface112 of the touch screen 110 at a location proximate to the electrode(s)126, 126A, 126B as the objects move across the insulating layer 116.

The controller 130 is configured to read an output of the sensor 118,which may be a voltage, and to identify a location of the input that wassensed by the sensor 118 via the output of the sensor 118 when thecontroller 130 is in a read mode. The controller 130 is also configuredto operate in a write mode in which the controller 130 writes a signal,which may be a voltage, to an electrode, such as the electrode 124 inthe conductive layer 114 (see FIG. 1) or the electrode 122 in theinsulating layer 116 (see FIG. 2) or the electrode 126 in between theconductive layer 114 and the insulating layer 116 (see FIG. 3), togenerate an electrostatic charge on, for example, the user's finger F.The electrostatic charge may be felt as an electrostatic output, whichprovides the haptic effect. The strength of the electrostatic output maydepend, among other things, on the thickness of the insulating layer 116that separates the electrode 122, 124, 126 from the skin of the user'sfinger F.

In an embodiment illustrated in FIG. 4, the insulating layer 116 mayinclude an outer insulating layer 116A that may be used to improve thestrength and durability of the touch screen 110. In an embodiment, theouter insulating layer 116A comprises glass. In an embodiment, the outerinsulating layer 116A comprises a thermoplastic. In an embodiment, asecond insulating layer 116B is provided in addition to the outerinsulating layer 116A. In an embodiment, the second insulating layer116B comprises glass. In an embodiment, the outer insulating layer 116Acomprises a thermoplastic having a thickness of less than 0.5 mm, andthe second insulating layer 116B comprises glass. In an embodiment, theinsulating layer 116 is a single layer of glass. In an embodiment, anelectrode 128 proximate to the outer insulating layer 116A may be usedspecifically for generating electrostatic outputs. Additional, dedicatedelectronics for driving the electrostatic outputs in the electrode 128,and also to coordinate the reading of the position and writing to theelectrostatic electrode 128 may be provided to minimize and even avoidpotential capacitive sensing issues.

In an embodiment, the controller 130 is configured to switch from a readmode in which the input or touch is sensed to a write mode in which avoltage is written or provided to generate an electrostatic charge andelectrostatic output on the touching finger F. The voltage may bewritten to at least one of the electrodes 122, 124, 126, 128 describedabove. This way, the haptic output device 100 is configured to multiplexbetween the sensing of the touch and the writing of the voltage togenerate an electrostatic change and electrostatic output on thetouching finger F.

In an embodiment, electrostatic outputs may be implemented bymultiplexing between reading the sensor 118 that senses a touch andwriting voltage to create the haptic effect. The voltage may be writtento at least one of the electrodes 122, 124, 126, 128 described above.This may be a general technique for both surface capacitive touchscreens and projected capacitive touch screens.

In an embodiment, multiplexing may be used between the sensing of thetouch and the writing of the voltage to generate an electrostatic chargeon the touching finger F. For surface capacitive touch screens, themethod may include reading the sensor 118 that has sensed a touch,switching from reading to writing, writing a desired voltage based onthe sensed location of the touch to create an electrostatic output,returning to reading the sensor 118, etc. The desired voltage may bewritten to at least one of the electrodes 122, 124, 126, 128 describedabove.

For projected capacitive touch screens, the method may include readingthe sensor 118 that has sensed a touch, obtaining a location of thetouch, switching from reading to writing (e.g., sensing to actuation),and writing a desired voltage to the area around the touch location.Because projected capacitive touch screen technology allows formulti-touch, different locations can be selected, and electrostaticoutputs may be applied to the specific locations without writing to thewhole touch surface area. The method may be repeated with the reading ofanother touch, etc.

The timing for the switching between the reading and writing (sensingand actuating) modes of the controller 120 may depend on the settlingtime of the signals.

In embodiments in which the touch screen 110 comprises multipleelectrodes, the ordering of the reading and writing may be adjusted. Forexample, in an embodiment, reading from a first electrode 126A whilewriting to a second electrode 126B (see FIG. 3) may occursimultaneously.

In an embodiment, a higher voltage may be used while sensing a touch tominimize and even avoid the need to set the read and write voltages totwo different levels. Typically, the electronics drivers use a smallvoltage for sensing, but this voltage may potentially be high enough togenerate electrostatic outputs. For a surface capacitive touch screenand a projected capacitive touch screen, an embodiment of a method mayinclude reading a touch position using traditional voltage levels,determining a touch location, and at the touch location, reading thetouch position by using electrostatic output voltage levels. Becausevoltage levels will be dynamic for electrostatic outputs, the processingof the sensing may be done by using this dynamic value. A potentialadvantage of this embodiment would be to minimize the time required towait for settling voltages between the read and write cycles.

For projected capacitive touch screens, the output may be localized,because different locations are known and may be accessed separately.

In an embodiment, the controller 130 may actively track the currentvoltage level for the read cycle, and adjust the value accordingly todetermine an accurate location of the input. In an embodiment, someelectrodes 140 may be read with normal voltage and other electrodes 140may be read with a higher voltage than the normal voltage.

If the area covered by the conducting layer 114 that includes at leastone electrode 124 in a projected capacitive touch screen is too small,the size may be modified in order to have a larger area to produceelectrostatic outputs. The haptic effect may be modulated as a functionof the area covered by the electrode, or as a function of the number ofelectrodes. For example, if different users with different finger sizesuse the same touch screen 110, or if a single user touches the touchscreen 110 with multiple fingers having different contact areas, such asa pinky and a thumb, the contact area information can be used to adjustthe magnitude of the haptic effect so that each finger perceives thesame haptic effect.

In an embodiment, a plurality of electrodes may be used instead of asingle electrode in order to create the haptic effect. In an embodiment,after the user input has been sensed, and the controller 130 may be usedto determine the optimum output location to minimize power or isolatethe haptic effect to a specific location. After the optimum outputlocation has been determined, the controller 130 may send signal todrive the electrode closest to the optimum output location.

In an embodiment, a user may provide multiple inputs to the touch screen110 with, for example, two or more fingers at two different locations.After the inputs have been sensed, the controller 130 may be used todrive different electrodes at different locations separately to createmulti-touch localized haptic effects. For example, the localized hapticeffects may be provided so that one finger feels a stronger hapticeffect than the other finger, or as the fingers are moved closer to oneanother across the surface 112 of the touch screen 110, the hapticeffect may change based on location of one finger relative to the other.

In an embodiment, the controller 130 may be configured to transitionhaptic effects from one electrode to the other as the user's fingermoves from electrode to electrode, and modulate the overall powerdelivered by each electrode according to the current location of theuser's finger. For example, the power delivered to the finger by eachelectrode may be a function of the finger's location relative to theelectrode. If the finger is located over a first electrode, the powerdelivered by the first electrode may be at level X to generate hapticeffect A. If the finger is located over a second electrode, the powerdelivered by the second electrode may be at level Y to generate hapticeffect B. If the finger is located in between the first electrode andthe second electrode, the power delivered to the first electrode may beone-half of level X and the power delivered to the second electrode maybe one-half of level Y to generate haptic effect C. In an embodiment,level X and level Y may be the same or substantially the same, andhaptic effects A, B, and C may be the same or substantially the same, sothat the haptic effect felt by the user is consistent across the surface112 of the touch screen 110.

The haptic effects may be generated one at a time, or can be combined.For example, a voltage may be applied to the conductive layer 114 at alevel high enough to both attract the skin of a finger F touching thetouch screen 110 and to stimulate mechanoreceptors within the skin.Simultaneous to this haptic effect, electrostatic forces may be producedon the conductive layer 114 and the insulating layer 116 (that includeselectrodes) to create mechanical motion in those layers.

FIG. 5 illustrates a method 500 for generating a haptic effect in ahaptic output device in accordance with an embodiment of the invention.The method 500 begins at 502. At 504, an input on the surface 112 of thetouch screen 110 is sensed with a sensor 118. At 506, a voltage is readfrom the sensor 118 that senses the input on the surface 112 of thetouch screen 110 by the controller 130. At 508, the location of theinput is determined by the controller 130. At 510, the controller 130 isswitched from a read mode to a write mode. At 512, a voltage based onthe sensed location of the input is written by the controller 130 togenerate an electrostatic output. The voltage may be written to anelectrode located at or near the sensed location of the input. At 514, adecision is made whether to continue the method or end the method. Ifthe method 500 is continued, the method 500 returns to 504 and anotherinput on the surface 112 of the touch screen 110 is sensed with thesensor 118. If the method 500 is ended, the method 500 ends at 516.

FIG. 6 illustrates a method 600 for generating a haptic effect in ahaptic output device in accordance with an embodiment of the invention.The method 600 begins at 602. At 604, an input on the surface 112 of thetouch screen 110 is sensed with a sensor 118. At 606, a voltage is readfrom the sensor 118 that senses the input on the surface 112 of thetouch screen 110 by the controller 130. At 608, the location of theinput is determined by the controller 130. At 610, a voltage based onthe sensed location of the input is written by the controller 130 togenerate an electrostatic output. The voltage that is written by thecontroller 130 is about the same as the voltage that is read by thecontroller 130. At 612, a decision is made whether to continue themethod or end the method. If the method 600 is continued, the method 600returns to 604 and another input on the surface 112 of the touch screen110 is sensed with the sensor 118. If the method 600 is ended, themethod 600 ends at 614.

Although the invention has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred embodiments, it is to be understood that suchdetail is solely for that purpose and that the invention is not limitedto the disclosed embodiments, but, on the contrary, is intended to covermodifications and equivalent arrangements that are within the spirit andscope of the appended claims. For example, it is to be understood thatthe present invention contemplates that, to the extent possible, one ormore features of any embodiment can be combined with one or morefeatures of any other embodiment.

1-20. (canceled)
 21. A haptic output device comprising: an insulatinglayer forming a surface of the haptic output device; one or moreelectrodes; a sensor configured to sense a touch input at the surface ofthe haptic output device; and a control circuit configured to sense, viathe sensor, the touch input on the surface of the haptic output device,to determine a size of a contact area between an object applying thetouch input and the surface of the haptic output device, and to apply anelectric signal to at least one electrode of the one or more electrodesto generate an electrostatic output with the at least one electrode,wherein a level of the electric signal is based on the size of thecontact area between the object applying the touch input and the surfaceof the haptic output device.
 22. The haptic output device of claim 21,wherein the electrostatic output simulates a friction force or textureas the touch input moves on the surface.
 23. The haptic output device ofclaim 21, wherein the one or more electrodes comprises a plurality ofelectrodes, and wherein the control circuit is configured to select fromamong the plurality of electrodes a closest electrode to a location ofthe touch input to generate the electrostatic output.
 24. The hapticoutput device of claim 21, wherein the level of the electrostatic outputis further based on a location of the touch input relative to the atleast one electrode.
 25. The haptic output device of claim 21, whereinthe level of the electrostatic output is further based on an impedanceof the surface at a location of the touch input.
 26. The haptic outputdevice of claim 21, wherein the control circuit is configured to applythe electric signal at a first level if the touch input is disposed overthe at least one electrode, and to apply the electric signal at afraction of the first level if the touch input is between the at leastone electrode and another electrode.
 27. The haptic output device ofclaim 21, wherein the haptic output device is part of a phone, a tabletcomputer, an automotive dashboard, or a steering wheel.
 28. A hapticoutput device comprising: an insulating layer forming a surface of thehaptic output device; one or more electrodes; a sensor configured tosense a plurality of touch inputs at the surface of the haptic outputdevice; and a control circuit configured to sense, via the sensor, alocation of a first touch input of the plurality of touch inputs and alocation of a second touch input of the plurality of touch inputs, andto apply an electric signal to at least one electrode of the one or moreelectrodes to generate an electrostatic output with the at least oneelectrode, wherein a level of the electric signal is based on thelocation of the first touch input relative to the location of the secondtouch input, wherein the electric signal causes the at least oneelectrode to generate an electrostatic output.
 29. The haptic outputdevice of claim 28, wherein the first touch input and the second touchinput are from two different fingers simultaneously touching the surfaceof the haptic output device.
 30. The haptic output device of claim 28,wherein the one or more electrodes include a plurality of electrodes,and the control circuit is configured to drive different electrodes ofthe plurality of electrodes at different locations to generatemulti-touch localized electrostatic outputs for the plurality ofrespective touch inputs.
 31. The haptic output device of claim 28,wherein the haptic output device is part of a phone, a tablet computer,an automotive dashboard, or a steering wheel.
 32. A haptic output devicecomprising: an insulating layer forming a surface of the haptic outputdevice; a plurality of electrodes comprising at least a first electrodeand a second electrode; a sensor configured to sense a touch input atthe surface of the haptic output device; and a control circuitconfigured to sense, via the sensor, a location of the touch input onthe surface of the haptic output device, to determine whether thelocation of the touch input is over the first electrode or is betweenthe first electrode and the second electrode, to write an electricsignal to the first electrode to generate an electrostatic output withthe first electrode, wherein the electric signal is applied at a firstlevel if the location of the touch input is over the first electrode,and wherein the electric signal is applied at a second level differentthan the first level if the location of the touch input is between thefirst electrode and the second electrode.
 33. The haptic output deviceof claim 32, wherein the second level is half of the first level. 34.The haptic output device of claim 32, wherein the control circuit isconfigured, if the touch input moves from a first location of the firstelectrode to a second location of the second electrode, to write asecond electric signal to the second electrode to transition theelectrostatic output from the first location to the second location asthe touch input is moved from the first location to the second location.35. The haptic output device of claim 34, wherein a level of the secondelectric signal depends on whether the location of the touch input isover the second electrode or is between the first electrode and thesecond electrode.
 36. The haptic output device of claim 32, wherein thehaptic output device is part of a phone, a tablet computer, anautomotive dashboard, or a steering wheel.